> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tryhamsa.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Real-time Transcription

> Stream audio for low-latency transcription

Hamsa provides two options for real-time speech-to-text:

* **Realtime API** (`POST /v1/realtime/stt`) — Send base64-encoded audio and receive the transcription directly in the response. Best for short audio clips.
* **WebSocket** (`wss://api.tryhamsa.com/v1/realtime/ws`) — Persistent bidirectional connection for streaming audio. Best for live conversations and continuous transcription.

## Realtime API

The Realtime API accepts base64-encoded audio and returns the transcription synchronously.

See the [Quickstart](/speech-to-text/quickstart#realtime-transcription-synchronous) for usage examples.

### Parameters

| Parameter      | Type    | Required | Description                                                 |
| -------------- | ------- | -------- | ----------------------------------------------------------- |
| `audioBase64`  | string  | Yes      | Base64-encoded audio data (WAV format)                      |
| `language`     | string  | No       | Language code: `ar` (default) or `en`                       |
| `isEosEnabled` | boolean | No       | Enable end-of-speech detection (default: `false`)           |
| `eosThreshold` | number  | No       | End-of-speech detection threshold, 0.0-1.0 (default: `0.3`) |
| `model`        | string  | No       | The STT model to use: `s2` (default) or `s3`                |

## WebSocket Streaming

The WebSocket API provides a persistent connection for streaming audio in real time. Send audio chunks as you record and receive transcription results as they become available.

### Endpoint

```text theme={null}
wss://api.tryhamsa.com/v1/realtime/ws
```

### Authentication

Authenticate via query parameter or header:

```bash theme={null}
wss://api.tryhamsa.com/v1/realtime/ws?api_key=YOUR_API_KEY
```

### Request Format

Send a JSON message with `type: "stt"`:

```json theme={null}
{
  "type": "stt",
  "payload": {
    "audioBase64": "//NExAAAAAANIAcAPABEAEQAQABEAEQARABEA...",
    "language": "ar",
    "isEosEnabled": true,
    "eosThreshold": 0.3,
    "model": "s2"
  }
}
```

### Response

The server sends the transcribed text directly as a plain string (not JSON).

For full WebSocket documentation including connection handling, error codes, and code examples, see the [WebSocket API reference](/websocket/websocket-api#speech-to-text-stt).